The present invention relates to a metering device. More particularly, the invention relates to a metering device for dispensing selected amounts of viscous material such as, for example, paste, cream, amorphic preparations, or the like.
There are many different types of known devices for dispensing viscous material. Plastic or metal collapsible tubes are used for dispensing viscous materials such as, for example, toothpaste, shaving cream, or the like. This type of device is incapable of accurately metering or measuring the amount of material dispensed. A relatively inaccurate metering or measuring device is a calibrated sheet of paper, or the like. This device depends for its operation upon the user.
A hypodermic syringe is a highly accurate device for dispensing materials. However, the operator must be trained in order to use it with accuracy and its operation depends upon such operator. Although measuring containers such as, for example, spoons, cups, or the like, are reliable and accurate as measuring or metering devices, they must be cleaned after each use. Measuring caps are utilized to provide the dual functions of closing the container of the material and metering or measuring the amounts dispensed. The caps must be cleaned after each use and are difficult to clean, since there is usually a residue therein.
Unit dose containers such as, for example, packettes or unettes, are ideal devices for dispensing predetermined measurements of material and are variable, since they may be made to contain more than a single premeasured amount of material. These containers are sometimes difficult to open, depending upon the material dispensed. Flexible squeeze containers or bottles, utilized with a reservoir of material, or filled with the material, may be utilized, but they must be cleaned after use.
Aerosol containers are used to dispense viscous material. Valves have been developed which permit the aerosol containers to dispense a specified amount of material. However, the containers are of large size relative to the amount of material stored therein, so that they are clumsy to handle.